Americans have been living through an enormously sensationalized college rape hoax, but as the evidence accumulates it's becoming clear that the entire thing was just a bunch of media hype and political opportunism.

No, I'm not talking about the Rolling Stone's lurid and now-exploded fraternity gang-rape story. Whatever the truth behind that story, it's now clear that basically nothing that Rolling Stone reporter Sabrina Rubin Erdely told us happened, actually happened. But the hoax is much bigger than one overwrought and perhaps entirely fictional tale of campus goings-on.

For months we've been told that there's a burgeoning "epidemic" of rape on college campuses, that the system for dealing with campus rape is "broken" and that we need new federal legislation (of course!) to deal with this disaster. Before the Rolling Stone story imploded, Sens. Claire McCaskill, D-Mo., and Kirsten Gillibrand, D-N.Y., were citing the Virginia gang rape as evidence of the problem, but now that the story has been exposed as bogus, they're telling us that, regardless of that isolated incident, there's still a huge campus rape problem that needs to be addressed as soon as possible.

And that's the real college rape hoax. Because the truth is that there's no epidemic outbreak of college rape. In fact, rape on college campuses is — like rape everywhere else in America — plummeting in frequency. And that 1-in-5 college rape number you keep hearing in the press? It's thoroughly bogus, too. (Even the authors of that study say that "We don't think one in five is a nationally representative statistic," because it sampled only two schools.)

Sen, Gillibrand also says that "women are at a greater risk of sexual assault as soon as they step onto a college campus."

The truth — and, since she's a politician, maybe that shouldn't be such a surprise — is exactly the opposite. According to the Justice Department's Bureau of Justice Statistics, the rate of rape and sexual assault is lower for college students (at 6.1 per 1,000) than for non-students (7.6 per 1,000). (Note: not 1 in 5). What's more, between 1997 and 2013, rape against women dropped by about 50%, in keeping with a more general drop in violent crime nationally.

Upshot: Women on campus aren't at more risk for sexual assault, and their risk is nothing like the bogus 1-in-5 statistic bandied about by politicians and activists. So why is this non-crisis getting so much press?

It's getting press because it suits the interests of those pushing the story. For Gillibrand and McCaskill, it's a woman-related story that helps boost their status as female senators. It ties in with the "war on women" theme that Democrats have been boosting since 2012, and will presumably roll out once again in 2016 in support of Hillary Clinton, or perhaps Elizabeth Warren. And University of Virginia President Teresa Sullivan hasn't apologized for her action in suspending all fraternities (and sororities) on the basis of a bogus story in Rolling Stone. Nor has she apologized for the mob mentality on campus that saw arrests, vandalism and protests at a fraternity house based, again, on a single bogus report. Instead, she's doubling down on the narrative.

This kind of hysteria may be ugly, but for campus activists and bureaucrats it's a source of power: If there's a "campus rape crisis," that means that we need new rules, bigger budgets, and expanded power and self-importance for all involved, with the added advantage of letting you call your political opponents (or anyone who threatens funding) "pro rape." If we focus on the truth, however — rapidly declining rape rates already, without any particular "crisis" programs in place — then voters, taxpayers, and university trustees will probably decide to invest resources elsewhere. So for politicians and activists, a phony crisis beats no crisis.

At least until people catch on. As George Washington University law professor John Banzhaf notes, "After a while, the boy who cried wolf wasn't believed, and the women who cry rape may likewise not be believed, especially with the accusations of rape at Duke University and the University of Virginia fresh in people's minds."

Even one rape is too many, of course, on or off of campus. But when activists and politicians try to gin up a phony crisis, public trust is likely to be a major casualty. It's almost as if helping actual rape victims is the last thing on these people's minds.

Glenn Harlan Reynolds, a University of Tennessee law professor, is the author of The New School: How the Information Age Will Save American Education from Itself.